Pyrosequencing-based barcodes for a dye-free multiplex bioassay.

A novel dye-free labeling method for a multiplex bioassay was proposed by using short sequence-based barcodes consisting of a reporter base and repeats of two stuffer bases; then, the barcodes were quantitatively decoded by a single pyrosequencing assay without any pre-separation.

[Development of 3-enzyme pyrosequencing system and its application in rapid diagnosis of Down's syndrome].

To avoid sequencing error resulting from use of apyrase in conventional 4- enzyme pyrosequencing system, a non-apyrase 3-enzyme pyrosequencing system with a better performance of quantitative analysis was established. The method is to immobilize biotinylated DNA template, ATP sulfurylase and luciferase on streptavidin-coated magnetic beads for pyrosequencing. After pyrosequencing, ATP produced from the pyrosequencing reaction and excess dNTPs were removed by magnetic separation technique; another dNTP was then dispensed for sequencing reaction, and the components interfering with the next circle of pyrosequencing reaction were removed by the same way, achieving the circular sequencing.

[Quantitative pyrosequencing of heterozygous single nucleotide polymorphisms for rapid diagnosis of Down's syndrome].

Objective: To establish a method to detect Down's syndrome through quantitative pyrosequencing of the heterozygous single nucleotide polymorphisms (SNPs) on the chromosome 21.

Methods: An improved allele-specific-amplification was used to screen heterozygous SNPs on the chromosome 21 from 84 normal samples. Pyrosequencing was used to quantitatively determine the ratio between the two alleles of a heterozygote, and the diagnosis of Down's syndrome was thus carried out based on the ratio.